This invention relates in general to viewing of a media production of a live event and more specifically where the viewer may select from multiple available video tracks with a single button press without any displayed screen graphics to assist the user with the switch.
To provide viewers the ability to view a media production of a live event, it may be transmitted live, over a cable system or by satellite or it may be stored on a compact disk (CD), a digital versatile disk (DVD) or other suitable storage medium. The DVD has recently become one of the most popular mediums for recording media productions because DVDs provide a large amount of storage capacity in an inexpensive small form factor. Typically, the media production is stored in a compressed, encoded form such as described in DVDs Demystified, Second Edition, 2001 published by McGraw Hill. During playback of the recorded media production, either a software decoder or a hardware decoder decodes the encoded media production. Software decoders comprise computer instructions executed by a computer-based device such as a personal computer system. Inexpensive hardware decoders are often sold as stand-alone DVD playback devices or as part of commercially available entertainment systems that need only be coupled to a display device.
Due to the random access nature of the DVD, viewers are able to randomly access various segments, tracks, streams or other portions of the media production during playback of the media production. Moreover, due to the large storage capacity, the DVD may store multiple video tracks of the media production with each track synchronized with other video tracks so that a viewer may switch from one track to another without experiencing any noticeable gaps in the video and audio. Multi-track video content is also referred to in the art as multi-angle content.
The interactive selection of video and audio tracks allows the viewer to select from one of several video tracks of the media production. Often, when more than one camera is used to film a media production, the video track from each camera is stored on the DVD so that the entire scene is made available to the viewer rather than just the single track prepared as the director's cut. A viewer may select one of several camera views provided on the DVD to modify their viewing of the media production. The viewer can scan the available tracks by pressing dedicated “angle” button on the DVD remote control device to select a different viewing angle. However, the use of dedicated buttons imposes constraints on both the director when preparing the media production for recording on the DVD and the viewer when attempting to access one of available video tracks. Notwithstanding the cumbersome nature of prior art video angle selection schemes, angle selection advantageously provides viewers some degree of control over viewing of a media production and as such is a very popular feature of DVD recorded media productions. Unfortunately, every DVD player interprets the multi-angle feature differently, making it difficult for directors to prepare multi-angle content for recording on DVD and for viewers to access the multiple synchronized video and audio tracks stored on a DVD.
To illustrate the problems that arise from the use of dedicated buttons for interactive selection of synchronized video tracks (e.g., “angles,” “scenes,” etc.), a number of problems arise. For example, one such problem is that the viewer can be confused whether a change of viewing angle resulted from the viewer's pressing of the dedicated “angle” button or was an edit in the initial video track. The confusion arises because the viewer is not certain that the video switch was completed. DVD “angle” button selections indications are confusing as it is not always obvious whether additional video tracks are available at any given time of playback or whether the additional tracks provide different unique viewing angles. This confusion is compounded because there is no standard mechanism for the viewer to know when additional viewing angles are available or to ascertain what content, if any, is present on alternate tracks recorded on the DVD.
Yet another problem arises because some DVD playback devices inform the viewer from a menu page at the start of playback that “camera 1” is a close-up view and “camera 2” is a wide view. Unfortunately, this solution requires the viewer to remember angle information for various cameras while viewing the media production. Clearly, this type of solution imposes an unnecessary burden on the viewer to recall camera placement while viewing the production. If the viewer forgets, the playback must be interrupted so that the menu page displayed so that a new angle may be selected. Not only is this process slow but the viewer's enjoyment is diminished because the delay in switching from one angle, to the menu page and then to a new angle interrupts the continuity of the media production. Compounding the viewer's problem is that other media productions may assign different angles to the cameras. Another drawback with this type of solution is that the film crew must strictly adhere to the disclosed camera placement when recording the media production.
Furthermore, variations and complexities in the viewer interface of most commercial DVD playback devices render playback systems unwieldy and confusing when new features are added to the DVD. Specifically, implementation of angle selection functionality differs from player to player, leading to user confusion, and slow user acceptance or comprehension of the feature. Typically, the viewer interface requires use of a specialized ‘angle’ button resulting in DVD playback device and entertainment systems that are unwieldy and confusing.
A typical control for stream switching is a DVD player, or television, handheld remote control. These familiar devices usually have a couple of dozen buttons for selecting channels, entering numbers, controlling the DVD transport (e.g., play, pause, skip, reverse), selecting a video source, and other options. Specific DVD players may provide a remote control, or other device, and interface for selecting or switching angles or scenes. In one approach, a DVD author assigns a video track (i.e., an angle or stream) to a specific button on the remote control. For example, numeric button “1” is used to select a first angle, button “2” a second angle, button “3” a third angle, and so on. However, with the prior art approaches it is often difficult for a viewer to know what angle will result from depressing a given key. This is especially true when the angles assigned to different keys change during playback of the DVD.
One approach to solving this problem is to provide on-screen “thumbnail” images of the different possible angles, or selections. Each thumbnail is a miniature version of the stream, or angle, selected upon pressing the corresponding button. For example, if the thumbnails are laid out left-to-right then the leftmost thumbnail can correspond to button “1,” the middle thumbnail to button “2” and the rightmost thumbnail to button “3.” Other ways to indicate thumbnail assignments to buttons are possible, such as by labeling each thumbnail with an adjacent numeral depending on the button association. An example of a DVD production that uses thumbnails can be found in, e.g., “Olympic Skating Exhibition Highlights,” Copyright 1998, CBS Worldwide, and copyright 1998 Panasonic Interactive Media Company, CD-PDV-0002.
A drawback with the thumbnail approach is that the thumbnails take up valuable screen space. Also, the thumbnails may be too small for a viewer to easily determine the nature of a stream or angle that will result from a selection. A redundant thumbnail of the currently-viewed track is usually needed as a placeholder so that the thumbnails on the screen maintain a visual correlation to control buttons. In other words, if there are 3 different angle choices, then there will always be three different thumbnails showing on the screen even though one of the thumbnails is just a miniature version of the full-screen currently selected track. Finally, the viewer is bothered by having to remember the respective associations and resulting button actions—a seemingly minor chore but one that can cause enough distraction to prevent the viewer from enjoying a production that is being played back from the DVD.
Approaches to improve upon user selection of streams or tracks during DVD playback are limited due to the need to comply with DVD standards. These standards, as promulgated by the DVD Forum dictate the requirements and limitations of specifying button assignments.
According to the standards, for single angle presentations, video, audio, subpicture, and navigation data are multiplexed together in what can be thought of as one continuous stream. A DVD player reads this information via laser pickup, loads it into a buffer, and then demultiplexes and processes the presentation (video/audio/subpicture) and navigation information.
The multiplex structure is illustrated in FIG. 6. FIG. 6 shows a portion of an object file of a DVD production having a single video angle with three audio streams and one subpicture stream. The format of a production in a stored medium such as a DVD is dictated in large part by the DVD standards. The object file that is used to create an end user product such as a DVD usually closely follows the same standard.
FIG. 7 shows an object file with multiple video angles. When multiple video angles are present each angle contains multiplexed data, as with the single-angle case, including subpicture data (containing button highlights) and navigational information (including button commands). The information is not shared across angles but, instead, is replicated in each angle. For example, a multiangle presentation with three audio streams ends up with the data for those three audio streams existing, redundantly, multiple times on the disc, in each angle. Each angle's data is interleaved within interleave units (ILVUs), which contain multiple blocks of video, audio, navigation, and subpicture data.
When a DVD player encounters an ILVU, it plays only the blocks containing data for the currently selected angle, skipping over the data for the other angles. The diagram of FIG. 7 shows the configuration of video, three audio, and one subpicture streams in a two-angle presentation.